Tamron SP AF28-75/2.8 XR Di LD Aspherical (IF) Macro

Lens shown in Nikon mount

The Tamron SP AF28-75/2.8 XR Di LD Aspherical (IF) Macro is a fast, general purpose lens for both digital and film cameras. On a film camera the 28-70mm range covers a lot of applications from landscapes and photojournalism to travel and environmental portraits. On a typical APS-C digital camera, such as the Canon EOS 20D, it has the same field of view as a 45-120mm lens would on a full frame 35mm camera. This range also has a number of "typical applications" but perhaps of most interest is that it covers the "portrait" range, which traditionally has been from about 80mm to 105mm.

Of course you can take portraits with anything from a wideangle to a telephoto, but most portraiture is done with short telephotos (80-105mm). A fast (f2.8) lens also lends itself to portraiture, where a smaller DOF gives a more diffuse background.

The Tamron SP AF28-75/2.8 XR Di LD Aspherical (IF) Macro is a Tamron "Di"
lens. Di lenses designed with digital SLRs in mind and Tamron say that they have higher
resolution, better control of flare and ghosting, less light fall-off and lower chromatic aberration than earlier designs.

Note that the Tamron SP AF28-75/2.8 XR Di LD Aspherical (IF) Macro has full frame 35mm coverage. Just because it's designated as a "Di" (digitally optimized) lens doesn't mean that it has reduced frame coverage like, for example, the Canon EF-S series lenses. You can use this lens on an APS-C sensor SLR (e.g. Canon EOS 20D) or on a full frame 35mm film body.

Tamron SP AF28-75/2.8 XR Di LD Aspherical (IF) Macro Specifications

Model Number

A09

Lens Construction (Groups/Elements)

14/16

Angle of View

75°-32°

Focal Length

28mm to 75mm

Maximum Aperture

f2.8

Diaphragm Blade Number

7

Minimum Aperture

f/32

Minimum Focus

0.33m (entire zoom range)

Macro Mag. Ratio

1:3.9 (at 75mm)

Filter Diameter

67mm

Weight

510g

Diameter x Length

73mm x 92mm

Accessories

Lens hood

Mount

Canon, Minolta-D, Nikon-D

The lens solidly constructed with a low reflectivity black finish
and a rubberized zoom control. It comes with a "petal" style detachable lenshood.
The barrel material appears to be plastic.

The zoom can be locked in the 28mm position so that the lens doesn't extend when being
carried in a downwards position.

Focus can be switched between AF and MF with a small switch on the left, near the lens
mount. Manual focus is smooth and well damped with about a 51
degree rotation of the rubberized focus ring from 0.33m to infinity. There are no depth of field scales and no IR focus identification mark.
It's marked with focal lengths of 28, 35, 50, 60 and 75mm

The lens extends when zoomed (from around 92mm long at 28mm to around 129mm long at 75mm), but does not change length on focusing (it's internal focus - IF) and the front of
the barrel does not rotate when the lens is zoomed or focused. However the focus ring does
spin during autofocus, so keep your hands away from it.

The Tamron SP AF28-75/2.8 XR Di LD Aspherical (IF) Macro uses three types of special optical elements as shown above. XR glass (extra refraction) is glass of high refractive index, used to keep the lens short. LD (low dispersion) glass is used to control and minimize chromatic aberration. Aspherical elements are used to minimize aberrations like spherical aberration which become more troublesome in fast lenses.

The lens has a close focus distance of 0.33m which gives a maximum
magnification of 1:3.9 at 75mm. Although the official name of the lens includes the term "macro", it's really
more accurately described as "close focusing". True macro lenses usually give 1:2 or 1:1 magnification and are specially optically corrected to ensure low distortion, flat field and high sharpness at very close focus distances.